1. Field of the Invention
The invention relates to a roller assembly that includes a roller which is supported on a roller bearing lever in a damping unit or an inking unit of a rotary printing machine, which roller can be pressed by a spring of a pressure mechanism against rollers lying adjacent to the roller and/or against a cylinder lying adjacent to the roller.
2. Description of the Prior Art
An inking unit in a rotary printing machine is already known from DE 22 49 920 C2 which has three inking rollers that lie adjacent to a form cylinder and are in contact with two distributor rollers, whereby two of the inking rollers lie adjacent to, respectively, one distributor roller each and the third inking roller lies adjacent to both distributor rollers. The bearing of one of the two distributor rollers is arranged via a roller bearing lever so as to be pivotable around the bearing of the transfer roller. The distributor roller presses two inking rollers, which are adjacent to the distributor roller, against the form cylinder under the influence of a spring. The inking rollers are also supported one under the other via springs. The adjustment of the contact area between the inking rollers, on the one hand, and the form cylinder, on the other, is performed via adjusting screws. This is meant to ensure an even, thin coating of ink on the form cylinder. However, adjusting the adjusting screws is expensive. A tool must be used to loosen the adjusting screws and then to tighten them again, while the given contact area between the rollers and the form cylinder in each particular case must be maintained. An adjustment procedure of this type is also very time-consuming. However, such a procedure is necessary, because the elastic surface of the rollers changes in diameter over time due to mechanical wear and to the chemical influences of ink and damping agents, requiring the roller to be readjusted repeatedly.
Another disadvantage of the known inking unit is that the inking rollers, due to their spring bedding, produce roller stripes on the form cylinder by swinging against it, which has a negative impact on print quality.